Piano action



P 1965 w. H. BENDALL 3,208,326

PIANO ACTION Filed July 12, 1965 United States Patent 3,208,326 PIANO ACTION Wilfrid H. Randall, R0. Box 126, Stonington, Conn. Filed July 12, 1%3, Ser. No. 294,721 9 Claims. (Cl. 84255) This invention pertains to piano actions and related apparatus for instruments utilizing playing key, percussion and vibratory elements for the performance of music.

As is well known to those skilled in the art piano actions are relatively complex mechanisms requiring a large number of delicate parts and necessitating costly assembly and regulating skills in manufacture. These practices are dictated in considerable part by adherence to a highly empirical design basis, traditionally thought to be essential for production of the established piano touch and tone. It is tacitly acknowledged in the art, however, that simpler, more efi'icient and lower cost action mechanisms would be highly desirable if they could be devised.

Accordingly, it is an object of the present invention to provide an improved piano action of greatly simplified design which will meet all the requirements of the established keyboard technique and further, to provide such action in a virtually noiseless and wearless mechanism, economical to manufacture and requiring a minimum of skilled adjustment and regulation in assembly and use.

Further objects and advantageous features of this invention are set forth in the following description and accompanying drawings in which FIGURE 1 illustrates the action assembly in a normal or unoperated position.

FIGURE 2 illustrates the assembly with the playing key depressed and the hammer at the instant of impact with a piano string.

FIGURE 3 illustrates the assembly with the key still depressed as in FIGURE 2 and with the hammer rebounded from the string and held for repetition.

FIGURE 4 is a fragmentary diagrammatic perspective view, on a larger scale, of a modified damper assembly construction.

In FIGURES 1 to 3 reference numeral designates a piano key pivoted at its rear end by fiat spring 11 to an action rail 12. The key is provided at its front end with downstop pad 13 at the base line 14, limiting key descent to its customary value. Supporting means normally provided for action rails such as brackets (not shown) may take a variety of forms and, with the action components mounted on the rail, permit installation and removal as a unit, the usual key frame not being required.

Action rail 12 conveniently comprises an extruded member having the sectional shape shown and cut to the required over-all length. Key ascent stop pad 15 is attached to the underside front edge of the rail and a hammer rest pad 16 to its upper rear edge. The forward edge of the rail is shaped to provide an arcuate recess 17 and a rounded top front edge portion 18. These two structural details serve for mounting and retention of the hammer pivot spring 19 provided with an arcuate end portion 20 adapted for sprung insertion and retention in the recess and having an intermediate spring portion 21 shaped for flexural bearing contact on the rounded front edge of the rail. A further extension 22 of this hammer pivot spring is bonded to the hammer shank 23.

The opposite end of the hammer shank is provided with a pivotally adjustable head comprising a segmental disk 24 of resilient material inserted in an arcuate clip 25 having pivotal extension 26 inserted in the hammer shank. The pivotal extension preferably is given a slight taper 3,298,326 Patented Sept. 28, 1965 to make it self-tightening in use. This hammer construction permits selective hammer head mass and angular adjustment relative to the angle and mass of the vibratory means, such as a piano string, which it is required to actuate. A further operating feature of this arrangement comprising incremental rotation of the disk 24 with each playing impact on the string 24a is as disclosed and claimed in a patent application filed coincidentally herewith and having Serial Number 294,720, and filing date July 12, 1963.

Attached to the key approximately at the center of its length is a fiat spring tensional link member 27. As shown in FIGURE 1 this member, in the unoperated position, is initially inclined toward the action rail. Its upper end 28 bears against the end of the hammer shank and is shaped to extend over the line of hammer pivotal bearing on the rail. This upper end portion further is shaped to facilitate a rocking bearing contact with the hammer shank during pivotal action of that member and its contact area with the hammer shank is lined or coated with a suitable resilient and sound-deadening material 29 such as a firm felt or synthetic rubber.

Spaced above and extending normal to the hammer shank axis is the damper shaft 30 having pivotal end portions 31 adapted for mounting in supporting brackets (not shown) of any convenient type. The usual pedalcontrolled arm (not shown) to rotate the damper shaft through its required small operating angle may be attached at either end or at any intermediate point. Damper element comprising lever 32 is held tangential to the shaft by a flat spring member 33 in peripherally sprung retention thereon and positioned by an indented locating end portion 34 engaging a groove in the shaft. An extension 35 of this spring member is bonded to the damper lever which is thus free to pivot tangentially and independently of the shaft within the required limited operating range. Respective end portions of the damper lever are provided with resilient string damping pad 36 and hammer shank contact pad 37. It should be observed that the damper assembly thus described permits alternative operation of the damper lever by the rising hammer shank, as shown in FIGURES 2 and 3, and by rotation of the damper shaft 30. The so-called loud pedal effect requiring removal of all damper pads from the strings is accomplished by anticlockwise rotation of the shaft (as viewed facing the drawing) to position the damper lever as shown in FIGURE 3, but it is important to note that individual damper elements are separately pivoted by the rise of the hammer shank to the position shown in FIGURE 2 independently of pedal actuation of the damper shaft. The so-called soft pedal effect is similarly accomplished, but by opposite or clockwise rotation of the damper shaft. This increases damper pressure on all the strings and simultaneously reduces the force of hammer impact by increasing resistance at the contact of the damper pad 37 with the rising hammer shank. While the damper construction herein disclosed differs in detail the method of tone control thus effected is as disclosed and claimed in the patent application above referred to and filed coincidently herewith.

Shown as in FIGURE 1 the parts of the action are in their normal position with the key 10 unoperated and with the damper pad 36 in light contact with the string. Depression of the playing end of the key to the limit of the downstop means 13 transmits a tensional pull to the flat spring link member 27 and pivots the hammer and damper elements to the relative positions shown in FIGURE 2. In this latter figure it will be seen that the link member has been rocked forward by its bearing contact on the hammer shank and by the hammer pivotal motion until only the tip of the link is in substantial "ice contact with the shank, resulting in a clearance space 38 between the end of the hammer and the link.

On further consideration of the relative position of the parts in FIGURE 2 it will be noted that while the key descent is definitely limited by the stop pad 13 the ham mer is free to pivot slightly beyond the point to which it is driven by the tensional pull of the link member and is limited in this only by the elastic yielding of the string under hammer impact. The hammer shank end may thus momentarily, without objection, escape its bearing contact with the extended tip of the link (following a heavy blow on the key, for example) but it normally remains in light contact therewith as shown. In this position also, the damper element is seen to be pivoted out of contact with the string by the rise of the hammer shank. If the playing key is immediately released after its maximum descent to the position shown in FIGURE 2 the parts at once revert to the positions shown in FIG- URE 1. If the key is held in the fully depressed position, as for a sustained tone, the parts assume the relative positions shown in FIGURE 3 on rebound of the hammer from the string. With the key held as described it will be seen that the tension link member has sprung back into contact with the projecting end of the hammer shank and, with the damper element still in contact with the hammer shank, holds the hammer in position for repetition of the note. The playing action thus accomplished can be repeated as rapidly as the physical ability of the performer permits and is virtually noiseless and frictionless in operation.

In constructing the action it should be noted that the extended portion 22 of the hammer pivotal spring may conveniently be preformed at a relative angle and have suflicient thickness to partly balance the overhanging weight of the hammer shank and head. Similarly, the key flexural pivot spring 11 may be utilized to partially balance the key in conjunction with the balancing force contributed by the hammer through the link 1-9 connecting these members. The spring mounting of both members may thus be utilized in any desired relative proportion to gain various action dynamic characteristics. The damper element spring 33 likewise may be variously proportioned to effect any desired degree of damper pressure and hammer rebound restraint.

Location of the damper assembly as shown in FIG URES 1 to 3, while spatially desirable in instruments having simple vibratile elements, may be less convenient in stringed instruments having unisons at a large relative angle to the hammer shank axis, or where string portions inside the hammer head orbit may be too short for effective damping. In such cases the damper assembly can be located outside the hammer orbit and an extension (not shown) of the tip of the hammer shank 23 utilized to engage the cushioning element 37 at the end of the damper lever 32.

The damper contact elements 36 and 37 also may alternatively be formed as continuous members resiliently interconnecting a plurality of damper levers. Hammer shank contact with the element 37 will then actuate a plurality of adjacent damper levers and remove the string damping element 36 from a plurality of string unisons. This damper modification is shown in the diagrammatic perspective view of FIGURE 4 in which a continuous string damping pad 36a and a continuous hammer shank contact pad 37a are shown securedas by bonding-to the damper levers 32. Actuating contact of an individual hammer shank with any part of the continuous cushioning element 37a will deflect a plurality of damper levers and result in corresponding deflection of the string damping element 36a. In all other respects the so-called loud pedal and soft pedal control of this modified damper assembly is accomplished as set forth above with reference to FIGURES 1 to 3.

It is to be noted that the resiliently interconnected damper structure thus described is highly advantageous for pianos since good piano tone depends for fullness and tone colour on the overtone complex. Hence, simultaneously removing damper contact from unisons adjacent to a specifically struck unison by the means described immediately above effectively supplements the overtone complex and enriches tone colour through increased sympathetic response of undamped adjacent unisons.

As again noted, the invention disclosed herein has certain features of hammer construction, key pivotal mounting and damper means in common with the invention disclosed in a coincidently filed patent application having Serial Number 294,720, and filing date July 12, 1963.

This invention further is disclosed in terms of particular embodiments thereof by way of example and is not necessarily limited thereto. Modifications of proportions and the materials of construction, which may readily occur to those skilled in the art, are considered to be fully within the scope of the invention as disclosed herein and as defined in the following claims.

I claim:

1. A piano action comprising a fixed rail having a tensionally linked hammer and playing key pivoted thereon, said key being pivoted at its rear end and having a limitedly movable playing surface at its front end and having a tensional link member comprising a length of flexible material extending from a point therebetween to a pivotal end of said hammer, the pivotal action thereof deflecting said link out of its initial alignment and relaxing said tension during hammer head approach to a piano string and the resilience of said link restoring said alignment after said approach.

2. The invention as recited in claim 1, including a pivoted shaft having damper means pivoted thereon, said damper means being selectively actuated by the pivotal action of said hammer and by the pivotal rotation of said shaft.

3. The invention as recited in claim 2, said damper means comprising a lever held tangential to said shaft by a flat spring member in sprung retention thereon and having a tangential extension thereof secured to said lever, said lever having resilient damping contact means at each end thereof and being adapted to pivot tangentially and rotate integrally with respect to said shaft.

4. The invention as recited in claim 1 including hammer shank pivotal means comprising a length of flat spring material having an intermediate portion shaped and arranged for flexural bearing contact on an edge of said fixed rail and having an end portion secured to a pivotal end of said hammer and an opposite end portion adapted for sprung insertion and retention in a recess in said rail.

5. The invention as recited in claim 4, said hammer having a pivotally adjustable head comprising a segmental disk and a pivotal extension thereof engaging the hammer shank.

6. A piano action comprising a fixed rail having a hammer pivoted on a forward edge thereof and a playing key pivoted on a rear edge thereof and tension transmitting spring means extending therebetween linking said hammer and key, said spring means having an upper end portion extending over and in rocking bearing contact with a pivotal end of said hammer, the pivotal actuation of said hammer rocking said contact to a point of lower resistance to hammer pivotal motion during hammer head approach to a piano string and the resilience of said link restoring said contact to its initial position immediately after said approach and holding said hammer against rebound.

7. A piano action comprising a fixed rail having a hammer and a limitedly movable playing key pivoted thereon and tension transmitting spring means extending therebetween linking the pivotal end of said hammer to said key, the pivotal action of said hammer extending beyond said limitedly movable key action and relaxing said tension during hammer head approach to a piano string, said tension being restored during hammer head rebound therefrom.

'8. The invention as recited in claim 7, including a damper shaft having a damper lever secured thereto and continuous string damping contact and hammer shank contact means resilient bridging said lever.

9. The invention as recited in claim 8, including hammer spring pivotal means and key spring pivotal means reciprocally balancing overhanging weight of said hammer and said key.

No references cited.

LEO SMILOW, Primary Examiner. 

1. A PIANO ACTION COMPRISING A FIXED RAIL HAVING A TENSIONALLY LINKED HAMMER AND PLAYING KEY PIVOTED THEREON, SAID KEY BEING PIVOTED AT ITS REAR END AND HAVING A LIMITEDLY MOVABLE PLAYING SURFACE AT ITS FRONT END AND HAVING A TENSIONAL LINK MEMBER COMPRISING A LENGTH OF FLEXIBLE MATERIAL EXTENDING FROM A POINT THEREBETWEEN TO A PIVOTAL END OF SAID HAMMER, THE PIVOTAL ACTION THEREOF DEFLECTING SAID LINK OUT OF ITS INITIAL ALIGNMENT AND RELAXING SAID 